[PATCH v2 00/12] KVM: arm64: Support FEAT_LPA2 at hyp s1 and vm s2

[Ryan Roberts]

Just a polite nudge: If anyone has any feedback on this series, it would be
great to hear it!

On 06/03/2023 19:54, Ryan Roberts wrote:
> Add support for FEAT_LPA2 to KVM for both hypervisor stage 1 (for the
> nvhe/protected modes) and the vm stage 2 translation tables (for all modes).
> FEAT_LPA2 enables 52 bit PAs and VAs for 4KB and 16KB granules (note this is
> already supported for 64KB granules via the FEAT_LPA and FEAT_LVA extensions).
> The series does not include support for FEAT_LPA2 in the kernel stage 1. This
> support is provided separately by Ard Biesheuvel's series at [1]. The two series
> are independent.
> 
> These patches are based on top of v6.3-rc1, plus 3 kvm selftests bug-fix
> patches, which I have posted separately at [2] and [3]. You can find a tree at
> [4]. Those bug-fix patches relate to incorrect test code for 52-bit PA (64K)
> guests, and are needed in order to test the new 52-bit 4K and 16K guest modes
> that this series enables.
> 
> 
> Testing:
> Testing has been done exclusively on the FVP and covers the boot matrix tests
> and kvm selftests.
> 
> The host/guest config boot matrix gives the same (expected) results as
> for the v1 submission; of 180 conifgs, 12 fail, and these are all due to
> attempting to load the host kernel into high memory which isn't expected to work
> until the kernel has FEAT_LPA2 support for its stage 1. (refer to v1 posting for
> details on the exact configs).
> 
> KVM selftests have been enhanced to support P52V48 4K and 16K guest modes, and
> all tests have been run against a P48V48_4K host and a P52V52_4K host (a run
> takes about 10 hours on FVP, sigh, but I can test a few more host configs if
> useful). All tests pass except "memslot_perf_test", which fails due to a timeout
> while syncing. This test fails in the same way for plain v6.3-rc1, so I'm
> confident this is not a regression caused by this series. (the issue is that
> alarm(2) is issued and the signal is received before alarm(0) is issued. I
> expect this is an FVP-time related problem, although I'm not sure how to fix
> robustly for the FVP without potentially hanging real systems for long periods
> of time).
> 
> 
> Changes since v1:
> https://lore.kernel.org/kvmarm/20221206135930.3277585-1-ryan.roberts@arm.com/
>  - Create CPU feature for LPA2 (enabled if both S1 and S2 report LPA2 support).
>  - Use the CPU feature (and therefore code patching) to globally decide whether
>    or not to use LPA2 PTE format; no more per-pgtable flag to pass around.
>  - Removed the range-based TLBI changes, which are not required by KVM; leaves
>    only minor changes to the non-range-based invalidation code.
>  - Removed patch to encode/decode VTCR_EL2.SL2, and replaced with a comment
>    describing why we never need to touch SL2 (stage 2 always uses concatenated
>    first level lookup).
>  - Added support for LPA2 guests in KVM selftests (VM_MODE_P52V48_4K enabled and
>    new VM_MODE_P52V48_16K added).
>  - Rebased onto 6.3-rc1.
> 
> 
> [1] https://lore.kernel.org/linux-arm-kernel/20221124123932.2648991-1-ardb@kernel.org
> [2] https://lore.kernel.org/kvmarm/20230228170756.769461-1-ryan.roberts@arm.com/
> [3] https://lore.kernel.org/kvmarm/20230302152033.242073-1-ryan.roberts@arm.com/
> [4] https://gitlab.arm.com/linux-arm/linux-rr/-/tree/features/lpa2/kvm_lkml-v2
> 
> 
> Anshuman Khandual (1):
>   arm64/mm: Add FEAT_LPA2 specific ID_AA64MMFR0.TGRAN[2]
> 
> Ryan Roberts (11):
>   arm64/mm: Update non-range tlb invalidation routines for FEAT_LPA2
>   KVM: arm64: Add ARM64_HAS_LPA2 CPU capability
>   KVM: arm64: Add new (V)TCR_EL2 field definitions for FEAT_LPA2
>   KVM: arm64: Use LPA2 page-tables for stage2 if HW supports it
>   KVM: arm64: Use LPA2 page-tables for hyp stage1 if HW supports it
>   KVM: arm64: Insert PS field at TCR_EL2 assembly time
>   KVM: arm64: Convert translation level parameter to s8
>   KVM: arm64: Support up to 5 levels of translation in kvm_pgtable
>   KVM: arm64: Allow guests with >48-bit IPA size on FEAT_LPA2 systems
>   KVM: selftests: arm64: Determine max ipa size per-page size
>   KVM: selftests: arm64: Support P52V48 4K and 16K guest_modes
> 
>  arch/arm64/include/asm/cpufeature.h           |  5 ++
>  arch/arm64/include/asm/kvm_arm.h              |  2 +
>  arch/arm64/include/asm/kvm_emulate.h          | 12 ++-
>  arch/arm64/include/asm/kvm_pgtable.h          | 72 +++++++++++------
>  arch/arm64/include/asm/kvm_pkvm.h             |  5 +-
>  arch/arm64/include/asm/sysreg.h               |  5 ++
>  arch/arm64/include/asm/tlb.h                  |  9 ++-
>  arch/arm64/include/asm/tlbflush.h             | 43 ++++++----
>  arch/arm64/kernel/cpufeature.c                | 40 ++++++++++
>  arch/arm64/kvm/arm.c                          |  4 +
>  arch/arm64/kvm/hyp/nvhe/hyp-init.S            |  4 -
>  arch/arm64/kvm/hyp/nvhe/mem_protect.c         |  6 +-
>  arch/arm64/kvm/hyp/nvhe/mm.c                  |  4 +-
>  arch/arm64/kvm/hyp/nvhe/setup.c               |  2 +-
>  arch/arm64/kvm/hyp/pgtable.c                  | 79 ++++++++++++-------
>  arch/arm64/kvm/mmu.c                          | 15 ++--
>  arch/arm64/kvm/reset.c                        |  9 +--
>  arch/arm64/tools/cpucaps                      |  1 +
>  .../selftests/kvm/include/aarch64/processor.h |  4 +-
>  .../selftests/kvm/include/kvm_util_base.h     |  1 +
>  .../selftests/kvm/lib/aarch64/processor.c     | 66 ++++++++++++----
>  tools/testing/selftests/kvm/lib/guest_modes.c | 42 +++++-----
>  tools/testing/selftests/kvm/lib/kvm_util.c    |  3 +
>  23 files changed, 297 insertions(+), 136 deletions(-)
> 
> --
> 2.25.1
> 
>